Hydrocarbon Processing - May 2022 - 29

Special Focus Biofuels, Alternative Fuels and
Green Petrochemicals
U. SCHMITZ, Atlas Copco Gas and Process,
Cologne, Germany; P. VAN LIMMEN, Dow Chemical,
Terneuzen, Zeeland, the Netherlands; R. WAGGEVELD,
BlueTerra, Veenendaal, Utrecht, the Netherlands
MVR compressor key to steam energy upgrade
at Terneuzen polyolefin plant
Reducing energy costs and creating
more sustainable local energy sources
are common challenges across many industry
sectors. Dow Chemical's process
plant in the Dutch municipality of Terneuzen
requires a considerable amount
of energy, often in the form of steam.
Tasked with the challenge of finding a solution
that would reduce its energy use,
engineers focused on the untapped potential
of low-pressure steam.
In an ongoing pilot project, the plant
uses mechanical vapor recompression
(MVR) to upgrade low-pressure steam
and reuse it to supply energy. Central to
the plant's MVR solution at Terneuzen
is a two-stage centrifugal compressor,
which compresses superheated steam
from 3 barg to 12.5 barg in two steps. The
result has been a reduction in natural gas
usage of around 10 million normal cubic
meters (MMNm³) in the last 12 mos and
a net reduction in carbon dioxide (CO2
emissions of 17.8 kilotons (kt).
)
Power to products: Electrification
and flexibility. In 2014, the Dutch government
initiated the " Power to Products "
project. Various companies from
the process industry, energy suppliers,
network operators and technology partners
came together to work on the initiative.
The project needed to address three
interrelated central points: how (technically,
operationally and organizationally),
at what cost and under what conditions
could the process industry make its electricity
demand more flexible. The aim
was to allow the process industry to use
cheap renewable electricity (wind and
solar) and, simultaneously, contribute to
grid stability. How this would be carried
out and under what conditions were the
underlying themes of the project.
The concept is straightforward. With
the introduction of more renewable energy
sources, the supply of sustainable
electricity would increase on windy and/
or sunny days. However, if the electricity
demand was low at such times, the price
would likely also be low, sometimes lower
than the gas price, and on occasion nearly
zero. The process industry could then
take advantage of this low power price.
With little wind or solar energy, the power
price would increase; during these times,
the industry could reduce its electricity
demand and contribute to the balance of
supply and demand.
How can the process industry achieve
this? The answer is twofold and revolves
around providing increased electrification
and greater flexibility. The first is electrification,
meaning the industry will use electricity
instead of fossil fuels, such as natural
gas. The second is flexibility, which
means that the process industry can offer
control of power requirements.
The process industry can do this in
two possible ways. One is by storing energy
during cheaper periods in the production
of chemical products and intermediates
such as hydrogen, pressure, heat or
cold thermal storage via charging and discharging.
They would then use the stored
products during more expensive periods.
The second method is to temporarily reduce
production and power demand at
expensive times and catch up later when
the price has decreased. In this method,
FIG. 2. Cross-section of an integrally geared
compressor core.
FIG. 1. Integrally geared compressor.
FIG. 3. Performance map for turbocompressor
using inlet guide vanes.
Hydrocarbon Processing | MAY 2022 29
Hydrocarbon Processing - May 2022

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